What are the indications for dual antiplatelet therapy (DAPT)?

Indications for Dual Antiplatelet Therapy

Dual antiplatelet therapy (DAPT) is indicated for patients with acute coronary syndrome (ACS) and those undergoing percutaneous coronary intervention (PCI) with stent placement, combining aspirin with a P2Y12 inhibitor for a standard duration of 12 months unless excessive bleeding risk exists. 1

Primary Indications

Acute Coronary Syndrome (All Types)

• DAPT is mandatory for all ACS patients (STEMI, NSTE-ACS) regardless of whether they undergo PCI or are managed medically. 1
• Standard duration is 12 months with aspirin plus a P2Y12 inhibitor (ticagrelor or prasugrel preferred over clopidogrel). 1
• This applies even in medically managed ACS patients who do not undergo revascularization. 1

Percutaneous Coronary Intervention with Stenting

• DAPT is required after coronary stent implantation in both stable coronary artery disease (CAD) and ACS settings. 1, 2
• For stable CAD patients undergoing elective PCI with drug-eluting stents, clopidogrel (600 mg loading dose, 75 mg daily) plus aspirin is recommended. 1
• Duration is typically 12 months for ACS patients and 6-12 months for stable CAD patients. 1

STEMI Patients Receiving Thrombolysis

• Clopidogrel (300 mg loading dose in patients aged <75 years, 75 mg daily) plus aspirin is specifically indicated for STEMI patients receiving fibrinolytic therapy. 1

Specific P2Y12 Inhibitor Selection Algorithm

First-Line Choice: Ticagrelor

• Ticagrelor (180 mg loading dose, 90 mg twice daily) is the preferred P2Y12 inhibitor for all ACS patients, regardless of treatment strategy (invasive or conservative). 1, 2
• This includes patients previously treated with clopidogrel, which should be discontinued when ticagrelor is started. 1, 2
• Ticagrelor is also the preferred agent for patients with prior stroke or TIA, as prasugrel is contraindicated in this population. 2

Second-Line Choice: Prasugrel

• Prasugrel (60 mg loading dose, 10 mg daily) should be considered in preference to ticagrelor specifically for P2Y12 inhibitor-naïve patients with ACS who proceed to PCI. 1, 2
• Dose adjustment required: 5 mg daily for patients ≥75 years or body weight <60 kg. 1
• Absolute contraindications for prasugrel: prior intracranial hemorrhage, prior ischemic stroke or TIA, ongoing bleeding. 1, 2
• Prasugrel is NOT recommended for medically managed ACS patients (without PCI). 1, 2

Third-Line Choice: Clopidogrel

• Clopidogrel (600 mg loading dose, 75 mg daily) is reserved for patients who cannot receive ticagrelor or prasugrel due to contraindications, intolerance, or unavailability. 1
• Specific indications include: prior intracranial bleeding, indication for oral anticoagulation, or high bleeding risk with inability to tolerate more potent P2Y12 inhibition. 1, 2

Duration Modifications Based on Bleeding Risk

Standard Duration (12 Months)

• All ACS patients should receive 12 months of DAPT unless contraindications exist. 1, 2
• This applies to both PCI-treated and medically managed ACS patients. 1

Shortened Duration (≤6 Months)

• Consider shortening DAPT to 3-6 months in patients with high bleeding risk (PRECISE-DAPT score ≥25 or meeting ARC-HBR criteria). 1
• Recent evidence supports that short DAPT (≤3 months) followed by P2Y12 inhibitor monotherapy (particularly ticagrelor) reduces bleeding without increasing ischemic events. 3

Extended Duration (>12 Months)

• Extended DAPT beyond 12 months may be considered in patients at high ischemic risk without increased bleeding risk. 1
• High ischemic risk includes: prior myocardial infarction, multivessel disease, diabetes, chronic kidney disease, or recurrent ACS. 1
• Ticagrelor 60 mg twice daily (reduced dose) can be used for extended therapy beyond 12 months in post-MI patients. 4

Critical Contraindications and Warnings

When NOT to Use DAPT

• Active pathological bleeding is an absolute contraindication. 5
• Prior intracranial hemorrhage contraindicates both ticagrelor and prasugrel (clopidogrel may be used). 1
• Life-threatening bleeding while on DAPT may require stopping both agents, but only if bleeding source cannot be controlled. 1

Pre-treatment Considerations

• Do NOT routinely pre-treat with P2Y12 inhibitors in NSTE-ACS patients when coronary anatomy is unknown and early invasive management is planned. 1
• Do NOT administer prasugrel in NSTE-ACS patients when coronary anatomy is not known. 1
• Pre-treatment with P2Y12 inhibitors is recommended for STEMI patients and when coronary anatomy is known with decision to proceed to PCI. 1

Bleeding Risk Mitigation Strategies

Mandatory Measures

• Use radial over femoral access for coronary angiography and PCI when performed by an expert radial operator. 1
• Maintain aspirin dose at 75-100 mg daily (not higher doses) when used with DAPT. 1
• Prescribe a proton pump inhibitor (PPI) in combination with DAPT to reduce gastrointestinal bleeding risk. 1, 2
• Pantoprazole and rabeprazole have the lowest propensity for drug interactions compared to omeprazole and esomeprazole. 1

What NOT to Do

• Do NOT perform routine platelet function testing to adjust antiplatelet therapy before or after elective stenting. 1
• Do NOT discontinue DAPT within the first month after stent placement for elective non-cardiac surgery. 1, 2
• Do NOT use higher aspirin doses (>100 mg daily) as this increases bleeding without improving efficacy. 1

Special Clinical Scenarios

Patients Requiring Oral Anticoagulation

• Triple therapy (DAPT plus oral anticoagulant) should be minimized in duration and intensity. 1
• Use clopidogrel (not prasugrel or ticagrelor) as the P2Y12 inhibitor component. 1
• Consider early transition to dual therapy (single antiplatelet agent plus anticoagulant) after 1 month in stable patients. 1

Perioperative Management

• Continue aspirin perioperatively if bleeding risk allows. 1, 2
• Resume full DAPT as soon as possible post-operatively. 1, 2
• Avoid elective surgery within the first month of DAPT initiation. 1

Switching Between P2Y12 Inhibitors

• In ACS patients previously on clopidogrel, switch to ticagrelor early after hospital admission with 180 mg loading dose, regardless of clopidogrel timing or loading dose. 1, 2